CMC - Certified Marine Chemist Confined Space Entry Requirements Questions and Answers

Question 1

According to OSHA 29 CFR 1915 Subpart B and NFPA 306, what is the correct order for atmospheric testing in a confined space prior to entry?

Accepted Answer

Oxygen content, flammability, then potential toxic contaminants.

Answer

The correct and safest procedure is to test for oxygen content first, as many combustible gas meters require sufficient oxygen to function correctly. Flammability is tested next, as it poses an immediate risk of fire or explosion. Finally, potential toxic contaminants are tested for, as their presence could be masked by other hazards.

Question 2

A Marine Chemist is called to certify a fuel oil cargo tank for hot work. The tank has been cleaned and ventilated. What is the maximum permissible Lower Explosive Limit (LEL) reading for the chemist to issue a 'Safe for Hot Work' certificate?

Accepted Answer

Exactly 0%

Answer

For a space to be certified 'Safe for Hot Work' under NFPA 306, the concentration of flammable vapors must be 0% of the Lower Explosive Limit (LEL). For a space to be 'Safe for Workers', the concentration must be below 10% of the LEL.

Question 3

A shipyard competent person has been monitoring a space certified as 'Safe for Workers' by a Marine Chemist. If a change in conditions occurs, such as the introduction of a cleaning solvent, which of the following actions is required?

Accepted Answer

Stop all work, re-evaluate the space, and potentially void the certificate.

Answer

Any change in the conditions of a space under which a Marine Chemist's certificate was issued invalidates that certificate. Work must be stopped, and the space must be re-evaluated to ensure it is safe for the intended operations.

Question 4

Under which of the following scenarios is a Marine Chemist's certificate MANDATORY before hot work can begin?

Accepted Answer

Welding on a bulkhead immediately adjacent to a tank that previously contained diesel fuel.

Answer

OSHA regulations (29 CFR 1915.14) and NFPA 306 require a Marine Chemist or a U.S. Coast Guard authorized person to test and certify a space as 'Safe for Hot Work' when the work is performed on surfaces immediately adjacent to spaces that have contained combustible or flammable liquids or gases.

Question 5

A Marine Chemist's certificate for a confined space specifies 'Enter with Restrictions.' Which of the following best describes what this designation implies?

Accepted Answer

Entry is permitted only if specific controls like continuous ventilation or PPE are used.

Answer

The designation 'Enter with Restrictions' means that entry for work is allowed, but only under specific conditions stipulated by the Marine Chemist. These restrictions could include requirements for continuous mechanical ventilation, specific personal protective equipment (PPE), atmospheric monitoring, or time limitations.

(CMC) Certified Marine Chemist Practice Test

(CMC) Certified Marine Chemist Practice Test

CMC - Certified Marine Chemist Confined Space Entry Requirements Questions and Answers